The Trijicon SRS (Sealed Reflex Sight) is a uniquely designed MIL-spec rugged,parallax free, reflex sight which incorporates a larger aperture for maximum situationalawareness in a shorter body. The illuminated 1.75 MOA red dot with 10 brightnesssettings (3 NVG compatible) is powered by a solar cell assisted by a single AA battery.The snag free button pads are easy to operate (eliminating fumbling under stressor with gloves).